As it stands, “with high greenhouse gas emissions, steeply declining reproduction and survival will jeopardize the persistence of all but a few high-Arctic subpopulations by 2100,” warns the
study, led by Peter K. Molnar of the University of Toronto Scarborough.
Even if emissions are reduced to more moderate levels, “we still are unfortunately going to lose some, especially some of the southernmost populations, to sea-ice loss,” Dr. Molnar said.
Global warming will cause the shrinking of sea ice in the Arctic, the study predicts, and therefore nearly all 19 sub-populations of polar bears will be forced onto land and away from their food supplies. The resulting lengthy periods of fasting, combined with reduced nursing of cubs by mothers, would allegedly lead to swift declines in polar bears’ reproduction and survival.
“There is very little chance that polar bears would persist anywhere in the world, except perhaps in the very high Arctic in one small sub-population,” Molnar
According to the study, “survival impact thresholds may already have been exceeded in some subpopulations.”
Many of the estimated 30,000 polar bears in the world depend on sea ice for their survival, hunting seals by waiting for them to emerge from holes in the ice.
“You need the sea ice to capture your food,” Molnar said. “There’s not enough food on land to sustain a polar bear population.”
The researchers predict that the bears will be forced to fast longer than they are capable of, based on their climate-model projections of ice-free days over the next 80 years.
“There’s going to be a time point when you run out of energy,” Molnar said.
The new study mirrors other similar studies and forecasts made over the last decades, all of which proved to be spectacularly wrong.
Polar bear populations have, in fact, proven remarkably resilient and despite some loss of Arctic summer sea ice, their numbers have in fact grown, a phenomenon
explored by climate skeptic Dr. Susan Crockford.
A 2007 report, for instance, predicted that the loss of two-thirds of the world’s polar bear population by the middle of the 21st century, while insisting that the forecast “may be conservative.” Since then, the polar bear population has continued to grow.
In 2005, the official global estimate was 22,500 bears. By 2015, that number had risen to 26,500 and is now thought to be around 30,000, the highest population in more than 50 years.
As Dr. Crockford points out, since polar bears do the bulk of their eating in the spring and fast for much of the summer, the presence of summer sea ice has relatively little to do with their feeding habits, a fact ignored by many of those predicting the bears’ demise.
Meanwhile, the population of ring seal pups in the spring — the polar bears’ main food — has also continued to rise, helping the bear population to thrive.
“Thriving polar bear populations have exposed the hubris behind global warming’s most beloved icon and the plight of the polar bears has become an international joke,” Crockford states.